BOSTON -- Boston Celtics rookie forward Jared Sullinger underwent back surgery Friday to repair a lumbar disc and will miss the remainder of the season, the team announced.

He is expected to be ready in time for training camp.

Sullinger left Wednesday's game against the Sacramento Kings just four minutes in with back spasms and did not return. Though he did not practice on Thursday and missed the team's morning shootaround on Friday, coach Doc Rivers and president of basketball operations Danny Ainge both initially downplayed the severity of the injury.